Often an implementation will choose a representation that facilitates pretty printing of the expression, so that (pprint `(a ,b)) will display `(a ,b) and not, for example, (list 'a b). However, this is not a requirement.

Implementors who have no particular reason to make one choice or another might wish to refer to IEEE Standard for the Scheme Programming Language, which identifies a popular choice of representation for such expressions that might provide useful to be useful compatibility for some user communities. There is no requirement, however, that any conforming implementation use this particular representation. This information is provided merely for cross-reference purposes.